Development of the XMv3 High Efficiency Cycloidal Engine

<div class="section abstract"><div class="htmlview paragraph">The increasing demand for environmentally friendly and fuel-efficient transportation and power generation requires further optimization and minimization of friction power losses. With up to 50% of the overall friction, the piston cylinder unit (PCU) shows most potential within the internal combustion engine (ICE) to increase mechanical efficiency. Calculating friction of internal combustion engines, especially the friction contribution from piston rings and skirt, requires detailed knowledge of the dynamics and lubrication regime of the components being in contact. Part I of this research presents a successful match of simulated and measured piston inter-ring pressures at numerous operation points [<span class="xref">1</span>] and constitutes the starting point for the comparison of simulated and measured piston group friction forces as presented in this research.</div><div class="htmlview paragraph">The authors utilized a single-cylinder floating-liner engine (FLE), based on a heavy-duty diesel truck engine, to determine crank angle resolved friction of the piston cylinder unit. The temperatures of the PCU were measured, and surface temperature distribution and thermal deformation were calculated to ensure realistic oil viscosity and piston and liner deformation under operating condition within the friction simulation.</div><div class="htmlview paragraph">Friction measurements were conducted under motored and fired engine condition. To derive the friction contribution of each ring and the piston skirt separately, motored strip-down tests were conducted as well. Piston ring friction was simulated with a validated ring dynamic simulation tool in combination with flow simulations of the surfaces using a deterministic correlation approach. To consider friction properly within the simulation, high-quality surface representation is needed. Precise optical three-dimensional measurements of the cylinder liner surface and the artificially surface generation for accurate numerical surface representation without measurement errors, revealed to be key. With the simulation model the friction contribution of each ring was compared separately with the strip-down measurement. Moreover, the piston secondary motion and the friction behavior of the piston skirt was calculated and compared to the measurements as well. As a result, the overall friction of the PCU was compared for motored and fired condition. The friction mean effective pressure (FMEP) as well as the crank-angle resolved friction forces from measurement and simulation were analyzed in detail. The comparison between simulation and FLE measurement was done for engine speeds from 10 to 1500 rpm, at oil temperatures from 40° to 100° C and engine loads up to 15.5 bar IMEP (indicated mean effective pressure).</div><div class="htmlview paragraph">The friction contribution (FMEP) of the simulation and measurement matches very well. The detailed examination of the crank angle resolved friction forces shows very good correlation for the hydrodynamic, and boundary lubrication regions.</div><div class="htmlview paragraph">This research successfully proves the ability to predict the friction forces and power losses of the different components of the PCU in combination with honed cylinder liners. It also reveals the importance of the quality of the input parameters such as surface topographies, surface temperatures respectively thermal deformations, oil parameters and contact geometries. Reliable input in combination with experimental data for the validation of the simulation models, enables the utilization of the simulation tools for reliable predictive design approaches.</div></div>

<div class="htmlview paragraph">Controlled Auto-Ignition (CAI) combustion, also known as HCCI or PCCI, has recently emerged as a viable alternative combustion process to the conventional spark ignition (SI) or compression ignition (CI) process for internal combustion (IC) engines, owing to its potential for high efficiency and extremely low emissions. One of the most effective and practical means of achieving CAI combustion in an engine is to retain or recycle the burnt gases. In order to understand better the effects of recycled burnt gases on CAI combustion, detailed analytical and experimental studies have been carried out. The analytical studies were performed using an engine simulation model with detailed chemical kinetics.</div> <div class="htmlview paragraph">The five effects of the recycled burned gases studied include:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"><span class="li-label">(1.)</span><div class="htmlview paragraph">Charge heating effect: higher intake charge temperature due to hot burned gases;</div></li> <li class="list-item"><span class="li-label">(2.)</span><div class="htmlview paragraph">Dilution effect: the reduction of oxygen due to the presence of the burned gases;</div></li> <li class="list-item"><span class="li-label">(3.)</span><div class="htmlview paragraph">Heat capacity effect: due to higher specific heat capacity of burned gases;</div></li> <li class="list-item"><span class="li-label">(4.)</span><div class="htmlview paragraph">Chemical effect: chemical reactions involving CO<sub>2</sub> and H<sub>2</sub>O in the burned gases</div></li> <li class="list-item"><span class="li-label">(5.)</span><div class="htmlview paragraph">Stratification effect: recycled burned gases are stratified from the fuel/air mixture.</div></li> </ol> </div> <div class="htmlview paragraph">And the main conclusions are:</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"><span class="li-label">(1.)</span><div class="htmlview paragraph">The charge heating effect is mainly responsible for the advanced AI timing due to hot burned gases. It increases the heat release rate and shortens the combustion duration.</div></li> <li class="list-item"><span class="li-label">(2.)</span><div class="htmlview paragraph">The dilution effect does not affect AI timing, but it extends combustion duration. Its slows down the heat release rate only when large amount of burned gases is present.</div></li> <li class="list-item"><span class="li-label">(3.)</span><div class="htmlview paragraph">The heat capacity effect is mainly responsible for the reduction in the heat release rate, and it has a similar effect to extend the combustion duration as the dilution effect.</div></li> <li class="list-item"><span class="li-label">(4.)</span><div class="htmlview paragraph">The chemical effect does not affect AI timing and heat release rate. It reduces the combustion duration slightly at high concentrations of burned gases.</div></li> <li class="list-item"><span class="li-label">(5.)</span><div class="htmlview paragraph">The stratified burned gases facilitate the CAI combustion due to the presence of higher temperature region at the boundary between of the hot burned gases and combustible charge.</div></li> </ol> </div>

<div class="htmlview paragraph">Several years ago some of the most prominent leaders in automotive industries cooperated to form a purely engineering group that had as its primary purpose developing a type of rigid-airship construction in which the public would have confidence. It was conceived that such an airship should be</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">(1)</span> <div class="htmlview paragraph">Fireproof</div> </li> <li class="list-item"> <span class="li-label">(2)</span> <div class="htmlview paragraph">Weatherproof</div> </li> <li class="list-item"> <span class="li-label">(3)</span> <div class="htmlview paragraph">Durable and permanent in structure</div> </li> <li class="list-item"> <span class="li-label">(4)</span> <div class="htmlview paragraph">Navigable in practically all kinds of weather</div> </li> <li class="list-item"> <span class="li-label">(5)</span> <div class="htmlview paragraph">Economical in the use of buoyant gas and ballast</div> </li> </ol> </div> <div class="htmlview paragraph">To meet all of these requirements it was decided, after mature consideration, that a substantially all-metal construction was imperative. Development of the Metalclad airship has now reached a point where the general soundness of the design seems fully assured as</div> <div class="htmlview paragraph"> <ol class="list nostyle"> <li class="list-item"> <span class="li-label">(1)</span> <div class="htmlview paragraph">The structural and aerodynamic efficiencies have been established by both analytical and experimental methods</div> </li> <li class="list-item"> <span class="li-label">(2)</span> <div class="htmlview paragraph">The technical problems involved in the construction have been mastered to a certainty hitherto unapproached in any new design</div> </li> <li class="list-item"> <span class="li-label">(3)</span> <div class="htmlview paragraph">The general design of an airship of demonstration size, 200,000 cu. ft. or one-tenth the size of the Shenandoah, has been completed</div> </li> <li class="list-item"> <span class="li-label">(4)</span> <div class="htmlview paragraph">Full-sized structural members of every part of the framework have been built and tested to destruction revealing that the minimum safety factor is double that of the Shenandoah. The longitudinal strength of the metal hull will be more than four times as great as that of the Shenandoah</div> </li> <li class="list-item"> <span class="li-label">(5)</span> <div class="htmlview paragraph">The problem of riveting the metal hull-plating has been solved through the perfection of an automatic riveting-machine</div> </li> <li class="list-item"> <span class="li-label">(6)</span> <div class="htmlview paragraph">The problem of making the metal hull gas-tight has been solved with surprising efficiency indicating an osmosis of about one-tenth that through gold-beaters skin and only one-hundredth that through rubberized fabric</div> </li> <li class="list-item"> <span class="li-label">(7)</span> <div class="htmlview paragraph">A suitable coating to prevent corrosion has been satisfactorily tested</div> </li> <li class="list-item"> <span class="li-label">(8)</span> <div class="htmlview paragraph">A source of supply of aluminum alloys of dependable quality is assured</div> </li> <li class="list-item"> <span class="li-label">(9)</span> <div class="htmlview paragraph">Shop facilities for fabrication are available in Detroit</div> </li> <li class="list-item"> <span class="li-label">(10)</span> <div class="htmlview paragraph">Skilled metal-workers familiar with aluminum and its alloys are at hand</div> </li> </ol> </div> <div class="htmlview paragraph">These results depend upon certain fundamental principles that are described in the paper. In effect, the design is an entirely new one, but adheres to the fundamental unalterable principles underlying all sound engineering-work.</div> <div class="htmlview paragraph">The paper states that the Metalclad airship is the last step in the development of rigid airships and most certainly must be adopted if such a means of transportation is to be made available both for the arms of National Defense and for commercial purposes.</div> <div class="htmlview paragraph">Appendices that include extracts from studies and texts arranged to illustrate the subject matter in the main paper and furnish food for discussion supplement the paper. This material is partially elementary in form as limitations of space preclude any attempt at completeness.</div>

<div class="htmlview paragraph">The effect of high compression ratio on cycle-to-cycle variability was studied using two different combustion chamber shapes, with natural gas operation. A single cylinder Ricardo E6 test engine was run over a range of operating conditions and compression ratios. The different combustion chamber shapes were achieved by using different pistons. At each operating condition detailed cylinder pressure data were recorded for two hundred consecutive cycles allowing for a detailed study of this chaotic phenomenon.</div> <div class="htmlview paragraph">The effect of compression ratio on cyclic variation was contradictory for the two combustion chambers, and it is concluded that the real effect was not compression ratio but combustion chamber shape, since the combustion chamber geometry was changed with altering compression ratio for both combustion chambers.</div> <div class="htmlview paragraph">Although good correlation between variations of maximum pressure and indicated mean effective pressure was not found, the pattern of the plot of peak cylinder pressure versus its location was found to have strong correlation with variation of indicated mean effective pressure.</div>

<div class="section abstract"><div class="htmlview paragraph">Future legislation scenarios as well as stringent CO<sub>2</sub> targets, in particular under real driving conditions, will require the introduction of new and additional powertrain technologies. Beside the increasing electrification of the powertrain, it will be essential to utilize the full potential of the Internal Combustion Engine (ICE). There is clearly a competition of new and different ICE-Technologies [<span class="xref">1</span>] including VCR. VCR systems are expected to be introduced to a considerable number of next generation turbocharged Spark Ignited (SI) engines in certain vehicle classes. The implementation of Miller or Atkinson cycles is an essential criterion for increased geometric Compression Ratio (CR). The DUAL MODE Variable Compression System (VCS)<sup>TM</sup> enables a 2-stage variation of the connecting rod length and thus of the compression ratio (CR). The concept allows a modular integration into existing engine families without significant modifications of the engine architecture and thus represents a cost-attractive solution. The basic functionality and potential were described in a technical paper which was presented at the SAE WCX 2017 [<span class="xref">2</span>], the development of the hydraulic function and oil investigations were presented at the SAE WCX 2018 [<span class="xref">3</span>].</div><div class="htmlview paragraph">This paper describes the engine integration of the Dual Mode VCS-system including the hydraulic control system into a state-of-the-art 2.0L-Turbo Gasoline Direct Injected (TGDI)-Engine for the vehicle boundaries of a midsize Sports Utility Vehicle (SUV).</div><div class="htmlview paragraph">Switching strategies, as well as the importance of short switching duration under Worldwide Harmonized Light Vehicle Test Procedure (WLTP) as well as Real Driving Emissions (RDE) requirements are discussed.</div><div class="htmlview paragraph">The applied fail-safe operation and Dual Mode VCS position control and detection will be described.</div><div class="htmlview paragraph">Finally, the Fuel Consumption (FC) impact of the Dual Mode VCS system is discussed. For the 2.0L-TGDI engine in the actual vehicle class, dependent on the load profile and the specific power and torque requirements a CO<sub>2</sub> reduction between 5% and up to 9% in the WLTP is achievable.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Diesel aftertreatment (AT) systems are critical for controlling emissions of CO, HC, NO<sub>X</sub>, and PM in the on-road transportation sector. Ensuring compliance with regulatory standards throughout the AT system's lifespan requires precise prediction of various degradation mechanisms under real-world operating conditions and mitigating their impact through proper catalyst sizing and advanced controls. In the SwRI A2CAT-II consortium, a medium-duty diesel engine production aftertreatment system was subjected to full useful life aging, involving chemical poisoning with phosphorus (P) and sulfur (S) species, along with hydrothermal aging following the DAAAC protocol. This study was aimed to model and predict the aging trajectory of this production AT system thereby capturing changes in system dynamics under both steady-state and transient conditions. The system, designed to meet the 0.2 g/bhp-hr standard, comprised a Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), and Ammonia Slip Catalyst (ASC). It was aged to 3600 hours equivalent to the DAAAC protocol and tested across a series of steady-state and regulatory cycles (HFTP, RMC, and LLC) at degreened, 33%, 66%, and 100% aging points. A linear decrease in system NOx conversion was observed between 0% to 66% aging, followed by a nonlinear drop from 66% to 100%. The cumulative decline in NOx conversion was 0.8%, which could significantly impact systems designed to meet a 0.05 g/bhp-hr target.</div><div class="htmlview paragraph">IntroductionAftertreatment durability demonstration is a mandatory validation exercise for on-road medium and heavy-duty diesel engine certification. This requirement ensures that the emission compliance can be achieved for the intended full useful life (FUL) of the engine system or multiple vehicle families. Conventional Deterioration Factor (DF) approach considers linear effect of sulfur and phosphorous poisoning on the catalysts over the entire useful life based on performance from 33% of aging the catalysts and extrapolating them to FUL. However, based on various studies, the impact of fuel derived Sulfur on diesel aftertreatment components was found to be exponentially significant particularly on the SCR due to the sulfur poisoning effect which require an active means to liberate sulfur to maintain appropriate SCR NOx conversion performance. Phosphorous from lubricating oil is known to adversely affect the activity of the oxidation catalyst in a catalyzed DPF thereby reducing the passive regenerative performance of DPF. For these reasons, an extensive understanding of chemical poisoning (particularly Sulfur and Phosphoros) and hydrothermal aging are warranted to design, validate and demonstrate the durability of aftertreatment components that are subjected to the prolonged chemical exposure.</div><div class="htmlview paragraph">To address the extensive challenges in durability demonstration, the Diesel Aftertreatment Accelerated Aging Protocol, or DAAAC, was developed by Southwest Research Institute as a part of consortium effort that includes input from diesel engine manufacturers [<span class="xref">1</span>, <span class="xref">2</span>, <span class="xref">3</span>]. DAAAC is an accelerated aging cycle developed for each application based on the available field data. It includes the exposure from hydrothermal aging, sulfur and lubricant derived poison at accelerated rates. The protocol also requires the entire aftertreatment system to be aged as a complete system, since the upstream components, such as DOC, can impact the chemical makeup of sulfur derived constituents.</div><div class="htmlview paragraph">The protocol does not introduce chemical constituents not normally observed in the field. The accelerated chemical exposure rate is limited only to a degree that has previously demonstrated successful correlation to normal, unaccelerated aging. The Protocol also requires that chemical aging mechanisms are to be introduced and / or consumed in a manner representative of the engine’s defined consumption pathways. Examples include sulfur exposure via high sulfur fuel or gaseous SO<sub>2</sub> and oil consumption via pre-combustion / post-combustion pathways. The Protocol also does not introduce chemical components that are not normally present in oil or fuel (other than doping the fuel with higher concentrations of sulfur, but this amount is relatively small). A comprehensive step by step breakdown of DAAAC protocol is presented elsewhere [<span class="xref">2</span>].</div><div class="htmlview paragraph">The primary objective of this paper is to disseminate the observation of long-term impacts of chemical poisoning and hydrothermal aging on a production aftertreatment catalyst subjected to FUL DAAAC protocol. The results of this experimental campaign were used to develop and validate a model capable of predicting hydrothermal and chemical aging mechanisms of conventional diesel aftertreatment to optimize long term emissions reduction performance. The paper is divided into following sections: <ol class="list nostyle"><li class="list-item"><span class="li-label">1</span><div class="htmlview paragraph">Introduction: An overview of the system</div></li><li class="list-item"><span class="li-label">2</span><div class="htmlview paragraph">Background: A review of literature in the field of diesel AT aging</div></li><li class="list-item"><span class="li-label">3</span><div class="htmlview paragraph">Test Campaign: Description of experimental setup used for collection of both steady state and transient data.</div></li><li class="list-item"><span class="li-label">4</span><div class="htmlview paragraph">Experimental setup: Description of burner stand used for data collection.</div></li><li class="list-item"><span class="li-label">5</span><div class="htmlview paragraph">Results and Discussion: Description of experimental results followed by discussion about underlying degradation mechanism identified through simulation work.</div></li><li class="list-item"><span class="li-label">6</span><div class="htmlview paragraph">Summary and conclusion</div></li></ol></div></div>

<div class="htmlview paragraph">A chemical and physical characterization of particulate emitted in undiluted exhaust of single cylinder direct injection (D.I.) diesel engine was made by an optical technique.</div> <div class="htmlview paragraph">On-line scattering and extinction measurements in the spectral range from 200 to 500nm were carried out in the exhaust ofthe engine operating under steady-state conditions. These measurements provided a useful tool for the comprehension of chemical and physical structure of the particulate. They allowed the evaluation in real time of the size, the concentration and also the optical properties. Preliminary results of size and mass concentration of particulate are presented.</div> <div class="htmlview paragraph">A good agreement was observed comparing the results with those obtained by gravimetric measurements, TEM and X-ray diffraction.</div> <div class="htmlview paragraph"><b>HIGH EFFICENCY OF DIESEL ENGINES</b> and their ability to burn heavy fuels make them ofgreat interest in the transportation field. On the other hand, present exhaust emission levels produced by this type ofengine will not satisfy stringent international regulations on environ- menta protection.</div> <div class="htmlview paragraph">The studies of the chemical and physical structure of diesel particulate in the exhaust of the engine help manufacturers both to optimize the efficiency of the combustion process and give useful information to designers of after-treatment devices.</div> <div class="htmlview paragraph">Historically, most studies on the particulate in the engine exhaust were carried out by electron microscopy and chemical analysis [<span class="xref">1</span>,<span class="xref">2</span>]<span class="xref">*</span>. These conventional techniques are time consuming, not real time, and not useful in transient operating conditions. Because the composition of the particulate materia depends on the collection system the data can be influenced by sampling procedures.</div> <div class="htmlview paragraph">Size distribution measurementtechniques of particulate based on electrical mobility, diffusion and inertial separation were proposed by Dolanetal.[<span class="xref">3</span>]. These techniques are real time but intrusive and can change the size distribution through collisions between particles.</div> <div class="htmlview paragraph">The recent advances in non-intrusive optical diagnostic techniques have made it possible to study on-line the evolution of particulate emitted in the exhaust with good temporal and spatial resolution.</div> <div class="htmlview paragraph">In the last decade, the optical measurements carried out in the exhaust, were made by nephetometry, transmissiometryor opacimetry, generally at a single wavelength in the visible range or in the infrared by photoacoustic and absorption measurements, These measurements are used to determine both the mass of particulate and the amount of dry soot and SOF [<span class="xref">4</span>,<span class="xref">5</span>,<span class="xref">6</span>,<span class="xref">7</span>.]</div> <div class="htmlview paragraph">In particular, simultaneous light scattering and extinction measurements at a single wavelength in the visible have provided a fast method to determine the dimension and concentration of soot particles i n flame [<span class="xref">8</span>].</div> <div class="htmlview paragraph">The purpose of the present study is to demonstrate the feasibility and flexibility of a new optical technique applied in the undiluted exhaustof a D.I. diesel engine. The technique consists of the use of simultaneous spectral measurements of scattering and extinction coefficients from the near ultraviolet to visible. These measurements allow the on-line simultaneous evaluation of the size, concentration and particulate mass as well as estimating the optical properties of the particulate. In particular, optical measurements in the near ultraviolet region are particularly promising because both graphite and large aro- maticmolecules exhibit absorption bands between 200 and 350nm [<span class="xref">9</span>,<span class="xref">10</span>].</div>

<div class="section abstract"><div class="htmlview paragraph">The present work represents the continuation of the introductory study presented in part I [<span class="xref">11</span>] where the experimental plan, the measurement system and the tools developed for the testing of a modern Wankel engine were illustrated. In this paper the motored data coming from the subsequent stage of the testing are presented. The AIE 225CS Wankel rotary engine produced by Advanced Innovative Engineering UK, installed in the test cell of the University of Bath and equipped with pressure transducers selected for the particular application, has been preliminarily tested under motored conditions in order to validate the data acquisition software on the real application and the correct determination of the Top Dead Centre (TDC) location which is of foremost importance in the computation of parameters such as the indicated work and the combustion heat release when the engine is tested later under fired conditions. In this testing phase much importance has been given also to the measurement of the frictions at the different operating rotational speeds. Interestingly, the data have been collected at three different coolant temperatures, 30°C, 60°C and 90°C respectively, in order to investigate and quantify any possible effect and interaction of the heat transfer on the mechanical and thermodynamics engine parameters for the usual operating temperature range. The collected data are subsequently used for the determination of the Friction Mean Effective Pressure (FMEP) to be employed in the computation of the Brake Mean Effective Pressure (BMEP) from the indicated pressure cycle or in the numerical models created for simulation purposes. Finally, still by means of the analysis of the indicated pressure cycle, further considerations are drawn on the thermo-fluid dynamics interactions of the three moving chambers with the self-pressurizing air-cooled rotor system (SPARCS) with its details already described in the first part of this suite of papers.</div></div>

<div class="htmlview paragraph">This report describes the possibility of quantitative analysis of Schlieren photographs as an internal combustion engine diagnostic.</div> <div class="htmlview paragraph">Using a recently developed photographic analysis system, it was attempted to analyze Schlieren photographs. Results showed simple integration calculations produced significant distortion in the analyzed results. To eliminate the distortion, some correction techniques were developed in this research. Accuracy of the analyzed results were evaluated roughly with uncertainty analysis. The results showed that this analysis technique can be one of the approximate diagnostics for the measurement of fuel vapor and density distribution in internal combustion engine research.</div> <div class="htmlview paragraph"><b>SCHLIEREN</b> photography is one of the most popular visualization techniques in the research of internal combustion engines. Although the photographs have density information in themselves, they are used mainly for the purpose of qualitative visualization. The objective of this research is to develop a quantitative analysis of Schlieren photographs for internal combustion engine research.</div> <div class="htmlview paragraph">One important parameter in engine research, for example, is the air entrainment in fuel jet vapor. Its measurement has previously been possible by gas sampling, laser holography, or laser Raman spectroscopy. The gas sampling method provides only point data, and the laser methods are very sensitive to vibration or optical settings. With this present Schlieren photographic analysis technique, it will be possible to measure instantaneously the whole space of the density field with a very simple optical system which is commonly used in engine research. Lakshminarayan and Dent(<span class="xref">1</span>)<span class="xref">*</span> analyzed interferometric photographs of jet sprays impinging on a wall. A major part of their (analysis method involved the counting of fringes which are sometimes difficult to distinguish in photographs. Nishida et al.(<span class="xref">2</span>)(<span class="xref">3</span>) analyzed Schlieren photographs reconstructed from laser holograms of jet vapor. However, they did not refer to the accuracy of the results.</div> <div class="htmlview paragraph">This report describes the background of the quantitative analysis and shows some analyzed results. The analysis was made for a CO2 jet injected into air. The Schlieren photographs were analyzed by an image processor and a personal computer.</div> <div class="htmlview paragraph">The results showed that the elimination of integrated error due to non-uniform background level was one of the most important parameters to be considered. In this study, a correction method is shown to determine the non-uniform background level and also to improve the accuracy of the results. This report also describes analyzed results for transient free jets and wall-impinging jets, which were compared with experimental results.</div>

<div class="htmlview paragraph">It is widely accepted that engine combustion is fundamentally affected by the in-cylinder charge motion. Flow field structures present at the time and location of spark ignition are known to have a controlling effect on early flame development. Therefore, improved understanding of the variation in flow field structures local to the spark plug at the time of ignition is required.</div> <div class="htmlview paragraph">This study investigates the spatial and temporal development of flow field structures within the pent roof combustion chamber of a single cylinder, direct injection spark ignition (DISI) optical engine. High speed particle image velocimetry (HSPIV) has been used to quantify the flow field leading up to and following spark ignition. HSPIV data was recorded at a rate of 5 kHz, providing a temporal resolution of 1.8 crank angle degrees (CAD) between measurement fields and a spatial resolution of 512 by 512 pixels. Velocity field measurements were acquired over a 70.2° crank angle (CA) range, from 300° CA to 370.2° CA after top dead centre (ATDC), spanning spark ignition (325° CA ATDC).</div> <div class="htmlview paragraph">Results show the spatial and temporal development of large scale bulk flow and small scale structures up to and following spark ignition. Comparison of individual cycles highlights the variation in flow field structures within the combustion chamber and the effect this has on engine performance. The levels of turbulence that exist within each cycle have been calculated as a root mean square (RMS) velocity and compared to engine performance indicated mean effective pressure (IMEP) and mass fraction burnt (MFB). In order to determine the range of spatial and temporal scales of turbulence that affect the burn rate and IMEP, frequency analysis was carried out on the HSPIV velocity field data. The results demonstrate the link between in-cylinder high frequency turbulence and engine performance, in terms of indicated mean effective pressure and burn rate.</div> <div class="htmlview paragraph">To assess the feasibility of using multiple injection strategies to control combustion, three different injection strategies were investigated. Single, double and triple injection strategies, occurring during the intake stroke to achieve a homogenous charge, were tested. Results indicate that even with early injection a higher level of turbulence intensity is generated within the combustion chamber at the time of ignition for the multiple injection strategies.</div>

<div class="section abstract"><div class="htmlview paragraph">In order to realize the Paris Agreement, which aims to strengthen the global response to climate change, conventional internal combustion engines (ICE) need to contribute to reducing carbon emissions and improving thermal efficiency. More importantly, in the face of energy shortages, it is urgent to search for sustainable fuels. Poly-oxymethylene dimethyl ethers (PODE) and methanol are both regard as important low-carbon, alternative fuels due to their high oxygen content. Using PODE can overcome the characteristics of methanol as a low-reactivity fuel with a low cetane number and poor ignition properties. In this study, the combustion and emission characteristics of PODE/methanol blends were investigated in a two-stroke direct injection engine. Firstly, the performance of the engine under pure PODE (P100) and PODE/methanol blends (P50) was compared. The results show that at BMEP of 0.31 MPa and injection timing of -8°CA ATDE, P50 blends have lower CO<sub>2</sub>, CO, NO<sub>X</sub> and THC emissions than P100 fuel. However, the start of combustion of P50 is delayed slightly and ITE is lower than that of P100. Then, the effect of injection timing on the performance of the P50 engine was investigated. With the delay of fuel injection timing, NO<sub>X</sub> emissions decrease, but CO<sub>2</sub>, CO, and THC emissions increase. Moreover, as the injection timing is delayed, the engine COV<sub>IMEP</sub> was reduced and combustion stability was improved. The engine indicated mean effective pressure (IMEP) reaches its maximum value of 0.441MPa at -8°CA ATDC and decreases as injection timing is delayed. However, the indicated thermal efficiency (ITE) decreases with the delay of injection timing, reaching a maximum of 41.8% at -8°CA ATDC. This study provides a theoretical foundation for adopting PODE/methanol blends in diesel engines, highlighting their potential to reduce conventional emissions while maintaining operational feasibility. Further research on varying methanol ratios and load conditions is recommended.</div></div>

<div class="htmlview paragraph">A modified version of KIVA II code was used to perform three-dimensional calculations of combustion in a DI diesel engine. Both an ignition delay submodel and a different formulation of the fuel reaction rate were implemented and tested.</div> <div class="htmlview paragraph">The experiments were carried out on a single cylinder D.I. diesel of 0.75 I displacement equipped with sensors to detect injection characteristics and indicated pressure. A fast acting sampling valve was also installed in the combustion chamber to allow the measurement of main pollutants during the combustion cycle, by an ensemble average technique. Computational and experimental results are compared and the discrepancies are discussed.</div> <div class="htmlview paragraph">Today the demand for light duty engines that produce less emission and consume less fuel is increasing. Thus, if limits on CO<sub>2</sub> emissions are established, the direct injection diesel engine for light duty applications will become an attractive option. Also, manufacturers of heavy duty diesel engines are facing increasingly stringent emission standards. New research efforts aim at improving DI diesels emission behaviour.</div> <div class="htmlview paragraph">Given the complexity of the interaction between the different processes in diesel combustion, comprehensive models of in-cylinder phenomena prove to be useful in providing guidelines for prototype development. Multidimensional analytical models of in cylinder phenomena have been greatly improved over the last decade, given the progress of the efficiency of computer hardware and diagnostic techniques. In particular many authors [<span class="xref">1</span>, <span class="xref">2</span>, <span class="xref">3</span>, <span class="xref">4</span>, <span class="xref">5</span>, <span class="xref">6</span> and <span class="xref">7</span>] have numerically simulated the interaction between the airflow field and the spray and have compared it with experimental data. However, both three dimensional calculations of combustion in the presence of fuel sprays and the corresponding comparisons with experimental data are hardly found in literature. In most cases the comparison between numerical and experimental results is limited to the pressure history and to the fitting of some pollutant emissions late in the expansion stroke.</div> <div class="htmlview paragraph">In particular, limiting the review to diesel combustion, Zellat and others [<span class="xref">8</span>] present calculations of a swirl chamber engine at different loads, injection timings, and speeds, obtained with a modified version of KIVA code. In their results, the computed in-cylinder pressure agrees well with the experimental one. Takeneka and others [<span class="xref">9</span>] used KIVA code to perform calculations of DI Diesel combustion for both swirl chamber and quiescent chamber systems. No details about the modifications introduced in the original code are provided.</div> <div class="htmlview paragraph">Computational comparisons with in cylinder measurements, performed in a quiescent chamber system by Kamimoto [<span class="xref">10</span>], show discrepancies between computations and measurements. Gonzales and others [<span class="xref">11</span>] also used the KIVA II code with the Reitz atomization model and a single step Arrhenius mechanism to describe combustion of tetradecane in a D.I. quiescent chamber engine. The paper focuses on the spray submodel effect on the accuracy of pressure history prediction. It was demonstrated that, if adequate grid resolution is used, prediction of combustion is sensitive to the details of combustion and fuel injection models.</div> <div class="htmlview paragraph">In the present paper a detailed comparison between experiments with a fast acting sampling valve and 3D calculations is presented for a medium duty swirl supported DI engine. Calculations are performed by KI-VA II code with the adoption of the TAB jet break up sub-model and wall impingement modelling. In addition, a different formulation of combustion model is discussed. The current status of the “numerical engine program” in progress at Istituto Motori of CNR, is thus defined.</div>

<div class="htmlview paragraph">Regulated and non-regulated emissions from five current European diesel passenger cars and one light-duty diesel truck were measured to assess the environmental impact of diesel vehicles and to help determine the emission characteristics of the two types of combustion systems: indirect injection (IDI) and high speed direct injection (HSDI). The vehicle emissions were measured using the European Motor Vehicle Emissions Group (MVEG) cycle and the U.S. Federal (FTP 75) test procedures. Measured emissions included HC, CO, NO<sub>x</sub> and particulate mass (PM), C<sub>1</sub> to C<sub>12</sub> hydrocarbon species (here called light hydrocarbon or LHC), aldehydes, particulate composition and particle size distribution. The particulate composition measurements included soluble organic fraction (SOF), its oil and fuel sub-fractions, and the sulfate fraction. All passenger cars and the light-duty commercial vehicle tested complied with the current European Emissions Directive 91/441/EEC. Two passenger cars achieved the EEC Stage 2 levels, and one nearly met the 1994 Tier I U.S. Federal standards. The LHC accounted for between 35 to 78% of the total HC measured by the heated FID analyzer. Fuel and oil comprised between 12 and 30% of the PM emissions. The non-methane organic gases (NMOG) emissions and the LHC ozone reactivity from diesel cars were both about 50% less than those from gasoline cars. Of the non-regulated emissions, formaldehyde was generally below 0.009 g/km, and benzene emissions were below 0.0035 mg/km. The results were compared with European gasoline vehicles and the Current Gasoline Vehicle fleet of the U.S. Air Quality Improvement Program (AQIRP), and an assessment was made of the relative environmental impacts of gasoline and diesel vehicles.</div> <div class="htmlview paragraph">Over the last 20 years, there has been a substantial effort to lower the exhaust emissions from both diesel and gasoline passenger vehicles. Over the same period, the percentage of diesel passenger vehicles purchased in Europe has been increasing steadily(<span class="xref">1</span>)<span class="xref">*</span>. Lower operating(<span class="xref">2</span>) and maintenance costs, and better durability with equivalent drive performance appear mainly responsible for the increased diesel sales. However, even though both diesel and gasoline vehicles meet the current emission standards, questions have arisen about their relative impact on the environment(<span class="xref">3</span>). In addition, with future requirements for lower emissions, these questions will undoubtedly continue.</div> <div class="htmlview paragraph">The relative environmental impact of diesel and gasoline vehicles is still uncertain because there are relatively few published data on the emissions of current diesel vehicles and because the environmental impacts of the expected emissions are not clearly understood. Data on the regulated emissions for diesel passenger vehicles sold in Europe are available from the German Government:(<span class="xref">4</span>) starting in 1991. There are also published reports on regulated emissions from late 1980 and early 1990 diesel cars in the literature(<span class="xref">5</span>,<span class="xref">6</span>,<span class="xref">7</span>). Still there are few reports on the non-regulated emissions from current diesel vehicles(<span class="xref">8</span>,<span class="xref">9</span>,<span class="xref">10</span>).</div> <div class="htmlview paragraph">On the other hand, there are substantial published data on the regulated emissions of current gasoline vehicles(<span class="xref">11</span>). In addition, there are substantial data on the non-regulated emissions of gasoline cars, especially from the U.S. Air Quality Improvement Research Program (AQIRP)(<span class="xref">12</span>). The AQIRP emissions data included measurements of over 150 individual hydrocarbon and aldehydic compounds which allow estimates of the amount of urban ozone formed from the exhaust and of the atmospheric toxic compound levels. Diesel vehicles were not included in AQIRP.</div> <div class="htmlview paragraph">This paper reports on detail regulated and non-regulated emissions measurements for six 1992/93 model year diesel vehicles, including two Ford and four competitor vehicles. The emissions were measured on both the 1993 European MVEG cycle and the U. S. Federal test procedure. The U. S. AQIRP analytical methods were used for hydrocarbon and aldehydic speciation. The report discusses the regulated emissions from the six diesel vehicles compared to emissions standards, their contribution to urban ozone formation, toxic levels and global warming. It also compares the exhaust emissions of current diesel and gasoline vehicles to help clarify their relative environmental impact.</div>

<div class="section abstract"><div class="htmlview paragraph">Selecting the right EMI/EMC filter is a major challenge when system noise levels exceed compliance or pre-compliance limits. Inline PCB filters are designed to mitigate noise in standalone conditions, but their behavior changes when integrated into a larger system due to unknown parasitic’s. These parasitic’s can disrupt electromagnetic compatibility (EMC), leading to non-compliance [<span class="xref">1</span>, <span class="xref">2</span>]. To address this, engineers often use off-the-shelf EMI filters, but determining their real-world effectiveness remains complex. Even with simulation-based methods, accurately predicting insertion loss and attenuation is difficult due to limitations in conventional modeling approaches [<span class="xref">4</span>, <span class="xref">5</span>].</div><div class="htmlview paragraph">Traditional SPICE-based simulations rely on static models defined at specific frequency points, with interpolated values for intermediate frequencies. This interpolation introduces inaccuracies, affecting the precision of simulated results [<span class="xref">6</span>, <span class="xref">8</span>]. To overcome these limitations, we propose a methodology that reconstructs a realistic EMI/EMC filter model based on insertion loss characteristics under symmetrical and unsymmetrical conditions.</div><div class="htmlview paragraph">Our approach involves deconstructing the EMI/EMC filter into its subcomponents—X-capacitance, Y-capacitance, common mode choke CMC, busbar, and PCB traces—and parameterizing them using CST simulations [<span class="xref">6</span>, <span class="xref">8</span>]. Instead of relying on physical measurements, which are prone to parasitic influences, we extract subcomponent values from datasheets. We focus on dominant parasitic elements exceeding 1 pF and 1 nH, as lower values predominantly affect GHz-range frequencies rather than the MHz-range compliance limits [<span class="xref">4</span>, <span class="xref">5</span>], analyzing impact of parasitic’s on insertion loss, resonance, and damping characteristics, a filter model that represents real-world behavior with a certain error percentage [<span class="xref">2</span>, <span class="xref">4</span>, <span class="xref">5</span>].</div><div class="htmlview paragraph">This methodology results in a high-fidelity EMI/EMC filter model with minimal deviation from actual performance. It enables precise pre-compliance conducted emissions simulations and facilitates optimized filter selection and tuning based on system-specific noise conditions.</div></div>

<div class="section abstract"><div class="htmlview paragraph"><b>Background</b>: The Indian automobile industry, including the auto component industry, is a significant part of the country’s economy and has experienced growth over the years. India is now the world’s 3<sup>rd</sup> largest passenger car market and the world’s second-largest two-wheeler market. Along with the boon, the bane of road accident fatalities is also a reality that needs urgent attention, as per a study titled ‘Estimation of Socio-Economic Loss due to Road Traffic Accidents in India’, the socio-economic loss due to road accidents is estimated to be around 0.55% to 1.35% of India’s GDP [<span class="xref">27</span>] Ministry of road transport and highways (MoRTH) accident data shows that the total number of fatalities on the road are the highest (in number terms) in the world. Though passenger car occupant fatalities have decreased over the years, the fatalities of vulnerable road users are showing an increasing trend. India has committed to reduce road fatalities by 50% by 2030. In this context, the automotive industry as well as MoRTH have been taking multiple initiatives including those related to vehicular and road engineering as well as educational measures for raising awareness in the field of road safety.</div><div class="htmlview paragraph">With the intent of lowering road traffic accidents, the government and the ministry are constantly upgrading the requirements related to vehicles, infrastructures, and their implementation thereof. In this context, various future regulations are being deliberated. One such regulation in discussion pertains to requirements for the protection of the passenger car occupants in the event of a full-frontal collision with a focus on restraint systems (AIS 201). This will push manufacturers to design more sophisticated restraints that would help to reduce restraint-induced injuries. The draft version of the standard is available for public input/ discussion.</div><div class="htmlview paragraph">The key objective of the study documented herein is to consider various aspects of the draft standard (AIS 201) from the Indian perspective. This study investigates the research questions, enumerated below: <ol class="list nostyle"><li class="list-item"><span class="li-label">1</span><div class="htmlview paragraph">What should be the appropriate test speed for the full-frontal test based on Indian accident data?</div></li><li class="list-item"><span class="li-label">2</span><div class="htmlview paragraph">What is the suitable dummy configuration in terms of gender, seating position, and age to maximize occupant safety in full frontal accidents?</div></li><li class="list-item"><span class="li-label">3</span><div class="htmlview paragraph">Is the proposed ATD’s anthropometry (weight and height) suitable, based on the people involved in full frontal cases in India?</div></li><li class="list-item"><span class="li-label">4</span><div class="htmlview paragraph">What are occupant injury attributes in full-frontal accidents?</div></li></ol></div><div class="htmlview paragraph"><b>Key findings/ expected research findings</b>: India has a very different mix of road traffic users and road traffic fatalities compared to that in Europe (Refer to <span class="xref">Table 1</span>). Further, issues like seat belt usage are of utmost concern. The demographic for India is also very different from those of developed economies. With India being a country with a rather young population, male and female dummies for driver and front passenger positions should be looked upon. This calls for India-specific safety regulations and research work on automotive test dummies.</div><div class="htmlview paragraph"><b>Practical implications</b>: The study can potentially provide a suggestion for alignment of the regulatory requirements with the actual situations, thereby increasing the effectiveness of the standard.</div></div>